Generic pistons are sufficiently known and are produced for example as cast or respectively as forged pistons. A covering of the cooling duct of such a piston, which is initially open on one side, usually takes place by means of a cooling duct cover in the manner of a metal sheet. The metal sheet itself already has here at least one inlet opening and an outlet opening, which are usually arranged adjacent to one another, so that there are almost 360° between the inlet opening and the outlet opening.
From DE 10 2008 038 324 A1 a piston is known having a cooling duct formed through a foundry core, which cooling duct has two inlet openings arranged adjacent to one another and two opposite outlet openings, separated from one another by a throttle. A cooling oil jet, incident obliquely to the piston axis, enters in the upper and lower dead centre through respectively one of the two inlet openings into the cooling duct.
From DE 10 2006 013 884 A1 a further piston is known for an internal combustion engine with a piston head and with a piston crown exposed to at least one combustion jet and with a piston skirt. The piston head and the piston skirt include here a circumferential outer cooling duct, wherein in the latter an annular dividing wall is provided, arranged parallel to the piston crown, which dividing wall has one or more nozzle-like openings which are arranged such that their respective outlet jet is directed parallel to the piston axis towards the underside of the piston crown. Hereby, the cooling effect of the cooling oil, supplied to the cooling duct, is to be improved.
From DE 10 2008 020 231 A1 a cast piston is known, which has a cooling duct formed through a foundry core. This cast cooling duct has an oil feed opening, which is arranged perpendicularly to the direction of the cooling duct and which has a funnel-shaped inlet to receive an oil jet directed parallel to the piston axis.
From EP 1 238 191 B1 a further generic piston is known, wherein in the region of an inlet opening a tube-like feed is fastened to the cooling duct cover by a snap-on connection or by clipping in.